1. Field
The invention relates to a coupling assembly for coupling a rod to a bone anchoring element, where the coupling assembly includes a receiving part with a recess for receiving the rod and an accommodation space for accommodating a head of the bone anchoring element. The coupling assembly further includes a pressure element to clamp the head and a rod receiving element that cooperates with the pressure element. The pressure element and the rod receiving element are configured to cooperate, such that when the anchoring element is inserted into the coupling assembly, the head of the bone anchoring element can be clamped first without fixing the rod, and subsequently the rod can be fixed using a single drive locking element. The invention further relates to a bone anchoring device including such a coupling assembly and a bone anchoring element. In addition, the invention relates to a kit including such a coupling assembly with different rod receiving elements to allow the use of rods with different diameters.
2. Description of Related Art
US 2010/0160980 A1 describes a locking mechanism and a method of fixation of a bone screw and a rod to the spine. The locking mechanism includes a body, an insert, a rod seat and a set screw. The body includes a bottom portion configured to receive the bone screw and the insert, but prevents the insert and the bone screw from passing therethrough once the insert and the bone screw are engaged. The rod seat is between the rod and the insert.
US 2013/0018428 A1 describes an orthopedic fixation device that includes a coupling element and a bone fastener, whereby the bone fastener can be loaded into the coupling element through the bottom of a bore in the coupling element.